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Perseids meteor shower peaks on August 13, 2015

The Perseids one of the finest annual meteor showers peaks this year on the night of August 12th/13th. On this date up to 100 meteors per hour can be seen under perfect conditions. This years event promises to be a good one as the New Moon won't interfere at all.

Recent analysis by NASA has rated the Perseids as the best meteor shower when it comes to fireballs. The shower is also extremely reliable, it rarely fails to deliver and has been observed for over 2000 years. Of all other annual showers only the December Geminids is comparable.

Discovery and Parent Body

The Perseids meteor shower is associated with comet 109P/Swift–Tuttle or as it's more often known comet Swift-Tuttle; a Halley-type object with an orbital period of 133 years. The Perseid cloud consists of particles ejected by the comet and stretches along the comet's orbit. It's believed that most of today's dust in the cloud is about 1000 years old, although some parts may be considerably younger. When the Earth passes through a replenished area the meteor rate is increased compared to the older part of the stream.

The Perseids were first recorded by Chinese observers in 36 AD with comet Swift-Tuttle independently discovered by Lewis Swift on July 16, 1862 and by Horace Parnell Tuttle on July 19, 1862. Computations of the orbit of the Perseids between 1864 and 1866 by Italian astronomer G. V. Schiaparelli revealed a very strong resemblance to the recently discovered comet and this was the first time a meteor shower had been positively identified with a comet. The years either side of perihelion, usually exhibit higher rates of Persieds meteors, as was the case during the last perihelion in 1992. Swift-Tuttle on this occasion was visible from Earth with binoculars.

Radiant

This meteor shower gets the name "Perseids" because it's radiant is located in the constellation Perseus. The radiant, the point in the sky where the meteors appear to originate from is positioned at right ascension (RA) 02hr 27m and declination (DEC) +58 degrees. This is close to the border with Cassiopeia and its well-known "W" shape asterism.

The meteors are visible from about July 17th to August 24th with rates starting low, gradually building up to the peak date, before falling off again afterwards. The shower is best seen from the Northern Hemisphere where the radiant appears high towards the northeastern part of the sky.

For those located in the Southern Hemisphere, the Perseid radiant is either very low down or even never climbs above the horizon. This considerably reduces the number of meteors likely to be seen, although it's possible to see a few meteors per hour coming up from the northern horizon.

To spot as many Perseids as possible the best advice is the find a dark observing site with an unobstructed view of the sky. Then scan a large area of sky surrounding the radiant but not directly at the radiant. The reason is that even though the meteors originate from the radiant, they usually appear many tens of degrees in the sky from it.